1. Field of the Invention
The invention is related to the field of communication networks and, in particular, to providing systems and methods that select a preferred foreign wireless network based on the number of roaming subscribers serviced by the foreign wireless network.
2. Statement of the Problem
A wireless network of a service provider includes a plurality of base stations, a plurality of Mobile Switching Centers (MSC), and one or more Home Location Registers (HLR). The base stations of the wireless network form the service area of the wireless network. The number of base stations operated (owned or leased) by the service provider determines the size of the service area. When a subscriber is located in the service area of the wireless network, the mobile device of the subscriber registers with the wireless network through one or more base stations in range of the mobile device. To register, the mobile device transmits a registration message that is received by a base station and is forwarded to an MSC serving the area (serving-MSC). The MSC then transmits a location update message to the HLR having a subscriber profile for the subscriber. The subscriber profile includes a real-time location of the subscriber. The HLR responds with an acknowledgement message to the serving-MSC.
The wireless network as described above has a limited service area that does not cover every location where the subscriber may travel. One such instance is when a subscriber travels to a foreign country where the service provider does not have a presence. To provide wireless service to subscribers who are roaming in areas not covered by the wireless network of the service provider (referred to as the home wireless network), the service provider will often contract with the other service providers (referred to as foreign service providers) having wireless networks (referred to as foreign wireless networks) to provide service in areas where the home wireless network is not able to provide service. If the mobile subscriber is roaming in a foreign wireless network and registers with an MSC in the foreign wireless network, then the serving-MSC in the foreign wireless network transmits a location update message to the HLR of the home wireless network. The HLR responds to the serving-MSC with an acknowledgement message and subscriber data allowing the serving-MSC to provide service to the mobile device. The serving-MSC stores subscriber data in a Visitor Location Register (VLR) as long as the mobile device remains an active roamer in the service area of the serving-MSC.
There may be many different foreign wireless networks and associated foreign service providers that are serving the areas not covered by the home wireless network. One problem for service providers is deciding which foreign service providers to contract with to provide the service in the uncovered areas. The home service provider may contract with multiple foreign service providers at first meaning that no one foreign service provider is preferred over the others. The mobile device of a roaming subscriber may register with any of the foreign service providers depending on how the mobile device is provisioned.
Over time a service provider may select one of the foreign service providers as a preferred foreign service provider based on the roaming rates that can be negotiated with the foreign service provider, and the size of the coverage area of the foreign service provider. If a preferred foreign service provider is selected, then the home service provider desires to have its subscribers register with the preferred foreign wireless network when roaming in certain areas. To accomplish this goal, the home service provider can configure a preferred roaming list (PRL) in its mobile devices with information on the preferred foreign wireless network. The PRL is a list of system identification numbers (SIDs) to permit roaming on other wireless networks. The mobile device will try to locate one of the foreign wireless networks on the PRL first when the home wireless network is unavailable.
One problem with the present methods of selecting a preferred foreign wireless-network for a particular area is that the preferred foreign wireless networks are selected based on roaming rates and coverage areas. Unfortunately, the foreign wireless network with the lowest roaming rates and the largest coverage area may not be the best selection for the preferred foreign wireless network for that area as other foreign wireless networks serving the roughly the same area may be able to serve more roaming mobile devices at any given time. Thus, the home service provider may not be selecting the foreign wireless network that can provide service to the largest number of roaming subscribers.